Re: [PATCH RFC 09/15] hw/virtio/vhost-shadow-virtqueue: specified vring placement

Hanna Czenczek <[email protected]> Mon, 3 Aug 2026 14:48:34 +0200
Newsgroups dev.linux.lists.virtio-fs,org.nongnu.qemu-devel
Message-ID <[email protected]>
On 24.07.26 00:30, Connor Kite wrote:
> By default svq vrings are placed in an anonymous memory map. As svqs
> will be leveraged to enable memory isolation in vhost-user, it is useful
> to be able to place the vrings in a shared isolation memory region.
>
> Adds the option to specify vring placement by providing a vring base
> address before starting the svq.
>
> Signed-off-by: Connor Kite <[email protected]>
> ---
>   hw/virtio/vhost-shadow-virtqueue.c | 22 +++++++++++++++-------
>   hw/virtio/vhost-shadow-virtqueue.h |  3 +++
>   2 files changed, 18 insertions(+), 7 deletions(-)

I would go beyond Stefan and say that I do really ask for explicit 
bounds checking on the area.

Besides that, `vhost_svq_stop()` still always calls `munmap()` on `desc` 
and `used` and that must absolutely not be done in case a fixed location 
was provided.

Also, it would be nicer to have a function to set the base address 
instead of having to modify the svq object directly.

Hanna